1. Field of the Invention
The present invention relates to an apparatus for controlling the operation of a spinning frame in relation to a roving bobbin exchange system, wherein almost exhausted roving bobbins of bobbin hangers of a creel of a spinning frame are intermittently exchanged for corresponding full packaged roving bobbins suspended by bobbin hangers of a bobbin carriage carried to a working position thereof on a supply rail arranged along the longitudinal direction of the spinning frame, by means of a roving bobbin exchange apparatus which is capable of moving along a spindle rail of the spinning frame, in parallel to the operation for piecing rovings between a starting-end of a roving of each full packaged roving bobbin being subjected to the roving bobbin exchange operation with a rear end of roving from a corresponding almost exhausted roving bobbin which is still supplying the roving to the spinning frame.
2. Description of the Related Art
The following apparatuses can be utilized as the above-mentioned roving bobbin exchange apparatus. Namely, the apparatus as disclosed in European Laid-open Patent Publication No. 0213962, which corresponds to Japanese Unexamined Patent Publication Sho No. 62-53425, whereby the roving bobbin exchange operation is applied to a spinning frame. In this spinning system, at the starting condition, half exhausted roving bobbins are suspended by respective back-row bobbin hangers in a creel of each spinning frame while full packaged roving bobbins are suspended by respective front-row of bobbin hangers in the creel, and therefore, when the above-mentioned half-exhausted roving bobbins become almost exhausted, as a first step, the almost exhausted roving bobbins are exchanged for roving bobbins having packaging condition of which has changed from full size to half size. In other words, all roving bobbins on the front row of the creel are exchanged for facing roving bobbins on the back row of the creel, to suspended all of the almost exhausted roving bobbins by the respective front row of bobbin hangers of the creel, and thereafter, the above-mentioned roving bobbin exchange operation is carried out and the almost exhausted roving bobbins of the front row of bobbin hangers in the creel of the spinning frame are intermittently exchanged for corresponding full packaged roving bobbins of the bobbin hangers on the bobbin carriage on the supply rail, from one end of the spinning frame to the other end thereof along the spindle rail during the spinning operation, in parallel to the operation for piecing a starting end of a roving of each full packaged roving bobbin with a rear end of a roving from a corresponding almost exhausted roving bobbin which is still supplying the roving to the spinning frame. In the above-mentioned operation, a unit operation applied to plural adjacent pair of a front and back bobbin hangers of the creel, facing each other, of the spinning frame is intermittently carried out from one end of the spinning frame to the other end thereof. In the other type of roving bobbin exchange apparatus applied to such a spinning frame, as disclosed in Japanese Unexamined Patent Publication Sho 62-205149 (U.S. patent application Ser. No. 089,604, now U.S. Pat. No. 4,799,353 of Jan, 24, 1989), half exhausted roving bobbins and full packaged roving bobbins are alternately suspended by the front row and the back row of the bobbin hangers in the creel of the spinning frame, respectively, in a condition such that each front row bobbin hanger suspending a half exhausted roving bobbin faces a corresponding back row bobbin hanger suspending a half exhausted roving bobbin, while each front row bobbin hanger suspending a full packaged roving bobbin faces a corresponding back row bobbin hanger suspending a full packaged roving bobbin, at the start of the spinning operation. Therefore, when the above-mentioned half exhausted roving bobbins reach an almost exhausted condition, each pair of such almost exhausted roving bobbins suspended by a corresponding front row bobbin hanger and back row bobbin hanger, facing each other, are exchanged for full packaged roving bobbins of the bobbin carriage on the supply rail, in parallel to the operation for piecing a starting-end of a roving of each full packaged roving bobbin being subjected to the roving bobbin exchange operation with a rear-end of a roving from the corresponding almost exhausted roving bobbin which is still supplying a roving to the spinning frame. In the above-mentioned roving bobbin exchange operation, usually a signal is outputted to request a roving bobbin exchange operation from the spinning frames, accordingly, the consumed condition of roving bobbins suspended by the bobbin hangers of the creel of the spinning frame is measured in each spinning frame, and when the size of the roving bobbins in the half exhausted condition reaches the almost exhausted condition in a certain spinning frame, the above-mentioned request signal is outputted from this spinning frame to call the roving bobbin exchange apparatus, as disclosed in Japanese Unexamined Patent Publication Sho No. 62-62929.
If the method disclosed in Japanese Unexamined Patent Publication No. Sho 62-62929 is combined with the roving bobbin exchange system utilizing the above-mentioned roving bobbin exchange operation, since the quantity of roving supplied is measured and the exchange of roving bobbins is carried out based upon the operative condition of each spinning frame with respect to the quantity of the roving bobbins, it is not necessary to stop the spinning frame for the roving bobbin exchange operation, and even if a spinning frame is stopped, an exchange of roving bobbins is not performed until the quantity of the roving of the above-mentioned half exhausted roving bobbins reaches a predetermined condition, i.e., an almost exhausted condition. This produces an advantage in that the quantity of the residual roving can be remarkably reduced so that the roving can be effectively utilized as the spinning material. Nevertheless, since one roving bobbin exchanging apparatus is utilized for a group of spinning frames, it is possible that an overlapping of demand signals requesting the bobbin exchange operation from a plurality of spinning frames will occur. In the conventional spinning frame, even after the output of the above-mentioned demand signal from a spinning frame, the spinning operation is still continued, and accordingly, in a spinning frame which has last outputted such a demand signal, it is possible that the above-mentioned half exhausted roving bobbins will be completely exhausted, and thus the end of a roving on a full packaged roving bobbin, which is being subjected to the roving bobbin exchange operation, cannot be connected to the rear end of the roving on the roving bobbins which should be maintained almost exhausted condition, however, was actually completely exhausted condition, and therefore a problem due to a discontinuation of the spinning operation arises.